A B C D E F G H I J K L M N O P Q R S T U V W X Y ZComets
A comet is a body that orbits the Sun and shows a tail when close to the Sun. Its nuclei is thought to consist of a collection of ice, dust and rocks. Comets are thought to originate in the Oort Cloud and/or the Kuiper Belt.
Links: Wikipedia - Comet Interactive Comet Animation Forum Thread - Comets OOTD on CometsConversion of RA & DEC
RA is measured in hours, minutes and seconds and can be stated as 8h 11m 43s
DEC is measured in degrees, arcminutes and arcseconds and can be stated as +15d 32’ 8”
On the SDSS Skyserver Object Explorer page (and elsewhere within SDSS) the RA and DEC values are given in degrees only, e.g. ra=130.43319704, dec=13.06579643
An online Convertion Tool
It is sometimes useful to be able to convert the SDSS values into the usual units for use elsewhere. If you already have an object from SDSS then use method (1) as this is the simplest.(1)
The information is at the top of the thumbnail image in the "Skyserver Object Explorer" page.
Beside thumbnail is: SDSS J084143.96+130356.8
This translates to ra = 08:41:43.96 dec = +13:03:56.8(2)
On a calculator:
If you have ra=130.43319704, dec=13.06579643
Enter 130.43319 (5 decimal places is OK)
Divide by 15 gives 08.6955467
The "08" is your Hours
Subtract 08 gives 0.6955467
Times 60 gives 41.7328
The "41" is your minutes
Subtract 41 gives 0.7328
Times 60 gives 43.968....
The "43.9" is your seconds
So RA = 08:41:44
Enter 13.06579 (5 decimal places is OK)
The "13" is your degrees
Subtract 13 gives 0.06579
Times 60 gives 03.9474
The "03" is your minutes
Subtract 03 gives 0.9474
Times 60 gives 56.84...
The "56.8" is your seconds
So DEC = +13:03:57
If the given dec value is negative, the final value is also negative.
[Thanks to Fermats Brother]Cosmic Rays
Cosmic rays are energetic particles originating from space. They are not "rays" at all but discrete particles. About 90% are hydrogen (protons), about 9% are helium. All of the other elements are present but constitute only about 1%.Cosmic ray detectors can measure slight differences in the energy and elemental and isotopic composition which indicate the source.
Known sources include the Heliosheath (very low energy), the sun (low energy), Galactic and extra-galactic which are primarily supernovae (high energy) and ultra high energy cosmic rays - believed to come from AGN’s and Gamma Ray Bursts. The energy depends upon the strength of the magnetic field that accelerated them.
They can affect light detectors and photographic plates and may show up on SDSS images
Links:Wikipedia link on Cosmic RayWikipedia link on Ultra-high-energy cosmic rayNASA's Imagine the Universe link on Cosmic Ray